The invention relates to a method for welding the surfaces of materials, of which at least one is glass, during which the energy that is required for the welding process is supplied by a laser beam.
Due to the specific properties of glass, it was required until now that glass which was to be bonded with another piece of glass or metal through fused mass had to be heated beyond the transformation point of the glass. In part it was also required to heat the areas that were to be fused together additionally, e.g. with flames. Subsequent to the welding process, the glass must cool down slowly to room temperature while avoiding stress, which could lead to breakage.
An example of the method of the kind described above is in U.S. Pat. No. 5,489,321, which shows radiation-absorbent material, e.g. a metal or a suitable oxide, is placed between glass panes in those areas in which the glass is to be welded together. Iron oxide, vanadium oxide or nickel oxide have proven to be particularly preferred radiation absorbent materials because the metal ions achieve their radiation absorption maximum around the emission wavelength of the Nd:YAG laser utilized in that example. The laser energy fed melts the glass of the glass panes due to thermal conduction through the metal or oxide, with the glass current of both panes becoming blended. This is also followed by the cooling process described above.
An objective of the invention is to provide a method for welding the surfaces of materials, of which at least one is glass, during which the cooling process no longer has to be monitored and controlled through readjustment.
These and other objectives are obtained by the invented method in which a laser beam is used and an intermediate sealing glass is applied between the surfaces that are to be welded together, and that the laser beam is adjusted in such a way that only the intermediate sealing glass is melted.